Hadronic energy resolution of a highly granular scintillator-steel hadron calorimeter using software compensation techniques

Abstract

The energy resolution of a highly granular 1 m 3 analogue scintillator-steel hadronic calorimeter is studied using charged pions with energies from 10 GeV to 80 GeV at the CERN SPS. The energy resolution for single hadrons is determined to be approximately 58%/ E/GeV. This resolution is improved to approximately 45%/ E/GeV with software compensation techniques. These techniques take advantage of the event-by-event information about the substructure of hadronic showers which is provided by the imaging capabilities of the calorimeter. The energy reconstruction is improved either with corrections based on the local energy density or by applying a single correction factor to the event energy sum derived from a global measure of the shower energy density. The application of the compensation algorithms to GEANT4 simulations yield resolution improvements comparable to those observed for real data.

The International Linear Collider Technical Design Report - Volume 4: Detectors

“…The linearity and the energy resolution -a key performance parameter even for a particle flow detector -of the AHCAL have been studied using pion beam at di erent energies [315]. In Figure III- 3.18(left) the reconstructed single particle energy is shown as a function of the beam energy.…”

“…The hadronic response for the AHCAL shows small deviations from linearity (less than 2% up to 80 GeV), mainly due to the non-compensating features of the structure (e/fi ≥ 1.19) [315] and to leakage. It can be predicted by simulations and was verified with test beam data.…”

Silicon photomultipliers in particle and nuclear physics

“…This saturation effect is addressed by the cellby-cell application of a correction algorithm which gives the expected true number of photons for a given number of fired SiPM pixels, as discussed in detail in [8], resulting in the recovery of a linear response of the calorimeter over a wide energy range. While the uncertainty of this saturation correction is the leading systematic in the energy reconstruction for electromagnetic showers of 40 GeV and above [8], it was found to be negligible for hadronic showers at all energies [9]. With local software compensation techniques used for energy reconstruction, the prototype achieved a hadronic energy resolution of ∼ 44%/ √ E[GeV] ⊕ 1.8% [9], with a response within 1.5% of linearity.…”

“…While the uncertainty of this saturation correction is the leading systematic in the energy reconstruction for electromagnetic showers of 40 GeV and above [8], it was found to be negligible for hadronic showers at all energies [9]. With local software compensation techniques used for energy reconstruction, the prototype achieved a hadronic energy resolution of ∼ 44%/ √ E[GeV] ⊕ 1.8% [9], with a response within 1.5% of linearity. Following the successful tests of the CALICE AHCAL physics prototype, the technology for highly granular scintillator-based calorimeters was further developed, as discussed in Section 3.3.…”

Development of highly granular calorimeters in CALICE

“…Most importantly, the AHCAL validated procedures for channel calibration and monitoring that account for the non-linear and T-dependent response of SiPMs. Also, it demonstrated powerful compensation techniques based on the energy density to reduce the shower stochastic fluctuations from 58%/ √ E to 45%/ √ E [14] while keeping a constant term smaller than 2 % (Fig. 2 left).…”